Generally, it is necessary to provide internal cooling of turbine components. To achieve high performance it is desirable to utilise high turbine entry temperatures and so greater thermal efficiencies. Unfortunately, such high turbine entry temperatures are limited by inherent characteristics of the materials from which turbine blades and vanes are made. In such circumstances, internal cooling allows components made from available materials to operate at temperatures which are close to, or exceed natural melting temperatures.
Cooling systems for turbine vanes and blades generally comprise providing a feed of cool air, taken from the compressor system in a jet engine, and feeding that cool air to the turbine blades through internal passages and chambers in order to effect cooling by a combination of internal convection and external film cooling.